Reusable Outer Cover For An Absorbent Article Having Zones Of Varying Properties

ABSTRACT

An absorbent article having a reusable outer cover and, optionally, an absorbent insert. The reusable outer cover has zones of varying properties. The properties of the different zones are varied to provide different performance features in different parts of the outer cover. The outer cover with zones of varying properties may provide competing or contradictory functionalities for improved comfort, fit, leakage protection, and aesthetic appeal.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/144,883, filed Jan. 15, 2009, which is herein incorporated byreference in its entirety.

FIELD OF THE INVENTION

This disclosure relates generally to absorbent articles, such asdiapers, training pants, adult incontinence devices, sanitary napkins,and the like, and more specifically, to a reusable outer cover for anabsorbent article, the outer cover having zones of varying properties.

BACKGROUND OF THE INVENTION

Reusable absorbent articles have traditionally involved an absorbentinsert, such as a cloth diaper, and a leak-resistant outer cover,usually including a heavy polymer film formed to resemble underwear.More recently, absorbent articles have become available with a reusableouter cover and disposable inserts. After the disposable insert issoiled, it is discarded, and a new disposable insert is placed in theouter cover, which may be cleaned or otherwise reconditioned prior toreuse. Additionally, new outer covers have become available which offerone or more benefits over past outer covers. Some of the newer outercovers may use non-traditional materials or constructions to make theouter cover more comfortable (softer, more flexible/more conforming tothe wearer), more breathable, and/or more aesthetically pleasing.Moreover, many of the newer outer covers achieve these benefits at theexpense of other desirable attributes of a reusable outer cover. Forexample, enhanced breathability may come with lower leakage protection,and softer materials may be less durable over multiple use cycles.

There remains a need for a reusable outer cover that can providecompeting or even contradictory properties to improve containment,wearer comfort, skin condition, and aesthetic appeal.

SUMMARY OF THE INVENTION

What is claimed is a reusable outer cover for an absorbent article. Thereusable outer cover may comprise a front zone and a rear zone, whereinthe rear zone has a greater percent extension than the front zone in theWhole Product Back Extension test. The rear zone may extend at least 50%under an applied force of 5N and may have an unload force of at least1.0N at 25% extension. The front zone may extend at least 15% under anapplied force of 5N.

The reusable outer cover may comprise a front zone, a crotch zone, and,a rear zone. The crotch zone may have a higher WVTR than the front andrear zones. The crotch zone may have a WVTR of at least 1200 g/m²/24hrs, or at least 3000 g/m²/24 hrs. The crotch zone may have a higherfluid penetration resistance than the front and rear zones. The crotchzone may have a fluid penetration resistance of at least 5 mbar.

The crotch zone may have a wearer-facing surface comprising a firstlayer and a garment-facing surface comprising a second layer, and thesecond layer may be more hydrophobic than the first layer. The secondlayer may be more hydrophobic than the front and rear zones.

The reusable outer cover may comprise a side zone, a rear zone, a frontzone, and a crotch zone. The side, rear, and front zones may have ahigher static coefficient of friction relative to skin than the crotchzone. The side, rear, and front zones may have a static coefficient offriction relative to skin greater than 0.5. The crotch zone may have astatic coefficient of friction relative to skin less than 0.4. The sidezone may have a higher static coefficient of friction relative to skinthan the front and rear zones. The side zone may have a staticcoefficient of friction relative to skin greater than 0.3.

The reusable outer cover may comprise an absorbent insert removablysituated against at least a portion of the crotch zone, and the crotchzone may have a higher static coefficient of friction relative to theabsorbent insert than the side, rear, and front zones.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1. is a plan view of an exemplary reusable outer cover.

FIG. 2 is a perspective view of an exemplary reusable outer coverconfigured for wearing.

DETAILED DESCRIPTION OF THE INVENTION

The term “absorbent article” as used herein refers to devices whichabsorb and contain body exudates and, more specifically, refers todevices which are placed against or in proximity to the body of thewearer to absorb and contain various exudates discharged from the body.Exemplary absorbent articles include diapers, training pants, pull-onpant-type diapers (i.e., a diaper having a pre-formed waist opening andleg openings such as illustrated in U.S. Pat. No. 6,120,487),refastenable diapers or pant-type diapers, incontinence briefs andundergarments, diaper holders and liners, feminine hygiene garments suchas sanitary napkins and panty liners, and the like. Absorbent articlesinclude reusable absorbent articles.

The term “disposable,” as used herein in reference to absorbentarticles, means that the absorbent articles are generally not intendedto be laundered or otherwise restored or reused as absorbent articles(i.e., they are intended to be discarded after a single use and,preferably, to be recycled, composted or otherwise discarded in anenvironmentally compatible manner).

The term “reusable,” as used herein means that a referenced material,component, or all of an absorbent article is configured to be restoredand/or reused for more than one usage cycle (e.g., a diaper change). Insome reusable absorbent articles, part, or parts, or substantially all,or all of the articles may be launderable or laundering resistant, asdefined and described herein. Another part or parts of a reusableabsorbent article may not be launderable or laundering resistant. Forexample, some parts of a reusable absorbent article may be discardedafter soiling and replaced with a new part, such as an absorbent insertwhich is used with a reusable outer cover.

The term “launderable,” as used herein means that a referenced material,component, or all of an absorbent article is configured to withstand alarge number (e.g. at least 10, in some embodiments up to 50, in otherembodiments more than 50) of cycles of machine washing and machinedrying (as defined by AATCC Test Method 124-2001, with modifications asdescribed below), without significant degradation to the appearance orperformance of the article that would render it unsuitable for itsintended functionality or use. Since hand-washing and line-drying aretypically less stressful on an absorbent article than machine washingand machine drying, it is expected that a material, component, orarticle that is machine washable and machine dryable should also behand-washable and hand-dryable for at least as many cycles. As anexample, a reusable absorbent article may include an outer cover that islaunderable. Launderable articles are designed to be suitable for useafter many washings, similar to types of clothing.

The term “laundering resistant,” as used herein means that a referencedmaterial, or component, or all of an absorbent article is configured towithstand a small number (e.g. at least one, in some embodiments up tofive, in other embodiments more than five) of cycles of machine washingand machine drying (as defined by AATCC Test Method 124-2001, withmodifications as described below), without significant degradation tothe appearance or performance of the article that would render itunsuitable for its intended functionality and/or use. As an example, areusable absorbent article may include an outer cover that is launderingresistant. Laundering resistant articles generally experiencedegradation after fewer laundering cycles than launderable articles.

The term “absorbent insert,” as used herein refers to a component of anabsorbent article used to capture or contain body exudates, and which isremovably associated with the absorbent article during use. For example,an absorbent insert may be press-fit into place, or may be releasablyattached to some portion of the absorbent article, as by mechanicalfasteners, adhesives, cohesives, and the like. An absorbent insert maybe disposable or reusable.

The term “wearer-facing,” as used herein means the side of an article orcomponent of an article that is nearest the wearer when the article isfitted to a wearer as intended for normal use. The term“garment-facing,” as used herein means the side of an article orcomponent of an article that is opposite to the wearer-facing surfaceand furthest from the wearer when the article is fitted to a wearer asintended for normal use.

As used herein, the terms “inboard” and “outboard” refer to the positionof an object relative to the longitudinal or lateral centerline of anabsorbent article. A first object is inboard of a second object if thefirst object is nearer the longitudinal or lateral centerline than thesecond object. A first object is outboard of a second object if thefirst object is farther from the longitudinal or lateral centerline thanthe second object.

As used herein, the term “zone” refers to a defined, macroscopic area ofan outer cover having at least one shared property or function acrossthe defined area. A zone of an outer cover may refer to all of thecomponents in the outer cover in the zone, or only a specified portionof the components of the outer cover in the zone. For example, a zonemay be limited to one surface of the defined area of an outer cover, ormay refer to multiple layers or multiple layered components within thedefined area making up the zone.

As used herein, the term “hydrophilic” describes surfaces which arewettable by aqueous fluids (e.g., aqueous body fluids) deposited onthese surfaces. Hydrophilicity and wettability are typically defined interms of contact angle and the strike through time of the fluids, forexample through a nonwoven fabric. This is discussed in detail in theAmerican Chemical Society publication entitled “Contact angle,wettability and adhesion”, edited by Robert F. Gould (Copyright 1964). Asurface is said to be wetted by a fluid (i.e., hydrophilic) when eitherthe contact angle between the fluid and the surface, is less than 90°,or when the fluid tends to spread spontaneously across the surface, bothconditions normally co-existing. Conversely, a surface is considered tobe “hydrophobic” if the contact angle is greater than 90° and the fluiddoes not spread spontaneously across the surface of the fiber. Contactangle is measured using a Kruss Drop Shape Analysis System, ModelDSA10-Mk2, as available from Kruss USA in Charlotte, N.C.

In order to enhance functional properties such as fit, wearer comfort,containment, skin condition and appearance of outer cover 10, it may bedesirable to fashion outer cover 10 to include zones of differentproperties to accommodate anatomical contours and body movements of theintended wearer, as well as the anatomic regions associated with bodilyexudate release from the body. Human anatomy in the lowertorso/hip/thigh region is asymmetric about the lateral plane of thebody, i.e., the geometry of the front of the human body is differentthan that of the back. Additionally, articulation of the waist and legsvia their respective joint and skeletal structures is asymmetric aboutthe lateral pane of the wearer, e.g., the torso bends preferentiallytoward the front of the wearer. Accordingly, different properties, suchas different stretch characteristics, may be desired in differentportions of an absorbent article. An outer cover for an absorbentarticle, for example, may include two or more zones having differentvalues for various functional properties, such as extensibility and/orelastic stretch, elastic recovery or unload force, breathability, fluidpenetration resistance or hydrohead, hydrophilicity/hydrophobicity, andcoefficient of friction.

General Structure of an Absorbent Article

As shown in FIG. 1, exemplary absorbent article 10 has outer cover 32.Outer cover 32 may have longitudinal axis 12 and lateral axis 14perpendicular to longitudinal axis 12. Outer cover 32 has front region16, back region 20, and crotch region 18 disposed longitudinally betweenfront region 16 and back region 20. Crotch region 18 of outer cover 32is the rectangle, defined below, that is centered longitudinally andlaterally about the article's crotch point. The crotch point isdetermined by placing absorbent article 10 on a wearer in a standingposition and then placing an extensible filament around the legs in afigure eight configuration. The point in the article corresponding tothe point of intersection of the filament is deemed to be the crotchpoint of the article. It should be understood that the crotch point isdetermined by placing the absorbent article on a wearer in the intendedmanner and determining where the crossed filament would contact thearticle.

With regard to sanitary napkins and pantiliners, the length of crotchregion 18 corresponds to approximately 60 to 100% of the outer cover'stotal length 50, generally about 80% of the outer cover's total length50. With regard to incontinence devices (e.g., diapers, adultincontinent articles) and other absorbent articles, the length of crotchregion 18 corresponds to approximately 40 to 80% of the outer cover'stotal length 50 (i.e., in the y-dimension), generally about 60% of theouter cover's total length 50. The width of crotch region 18 isequivalent to the width 30 of outer cover 32 of absorbent article 10 asmeasured at the crotch point. By way of illustration, for an incontinentarticle outer cover having a length of 20 in. and a width at the crotchpoint of 4 in., the crotch region is the rectangle, centered on thecrotch point, having a length of 12 in. and a width of 4 in.

Absorbent insert 22 may be attached at attachment points 24 and servesto capture or contain body exudates, such as urine, feces, menses,perspiration, etc. As shown, absorbent insert 22 is attached to outercover 32; however, absorbent insert 22 may be attached to any componentof absorbent article 10, or to an intermediate layer other than outercover 32, if present. Two attachment points 24 are shown proximate thelongitudinal ends of absorbent insert 22, however, absorbent insert 22may be attached at any number, shape, or pattern of attachment pointssuitable for keeping absorbent insert 22 in its intended position, forexample, proximate the anatomical source of body exudates, during use.In some embodiments, absorbent insert 22 may be held in place primarilyor exclusively by an outer cover zone having a high coefficient offriction, as described below, in which embodiments there may be nodistinct attachment point 24, or, rather, there may be one relativelylarge attachment point 24. In some embodiments, absorbent article 10 hasan integral absorbent core, and may or may not be attached to removableabsorbent insert 22 for supplemental absorbency. Absorbent insert 22 maybe shaped to provide improved wearer comfort and aesthetics. Forexample, absorbent insert 22 may have a generally hourglass shape toprovide improved fit between and around the wearer's legs.

Outer cover 32 has laterally opposed longitudinally extending edges 26and longitudinally opposed laterally extending edges 28. Longitudinallyextending edges 26 and laterally extending edges 28 are shown asstraight lines, however, longitudinally extending edges 26 and laterallyextending edges 28 may be contoured. For example, longitudinallyextending edges 26 may be shaped to more comfortably accommodate thewearer's legs, and laterally extending edges 28 may be shaped to morecomfortably accommodate the wearer's stomach, hips or back. In thespecific case of an infant diaper, laterally extending edge 28 may havea shaped profile in the front region to accommodate an umbilical cordstump. Other contours are possible. In FIG. 1, width 30 of outer cover32 at the crotch point is roughly the same as width 195 betweenlongitudinally extending edges 26 at the rear waist, however, inembodiments having longitudinally extending edges 26 which arecontoured, these widths may differ.

Outer cover 32 has a front zone, extending laterally betweenlongitudinally extending edges 26 of outer cover 32 and longitudinallybetween front waist edge 34 and front edge 38 of crotch region 18. Outercover 32 has a rear zone, extending laterally between longitudinallyextending edges 26 of outer cover 32, and longitudinally between rearwaist edge 36 and rear edge 40 of crotch region 18. Outer cover 32 has acrotch zone, extending laterally between longitudinally extending edges26 of outer cover 32, and longitudinally between front edge 38 and rearedge 40 of crotch region 18. Outer cover 32 has a side zone, extendinglaterally around the entire waist circumference when absorbent article10 is fitted to a wearer. That is, the side zone encompasses two fullwidths of outer cover 32, including the side panels, if present, on eachside. The side zone extends longitudinally a distance equal to length 42of front side panel 46 or length 44 of rear side panel 48, whichever isgreater. If there are no side panels, the side zone extendslongitudinally a distance equal to the length of the front zone in frontregion 16 and a distance equal to the length of the rear zone in backregion 20.

Outer cover 32 has a waist zone extending laterally along the entirewidth of front waist edge 34 and rear waist edge 36, inclusive of thewidth of front side panels 46 and rear side panels 48, if present. Thewaist zone extends longitudinally approximately 5 to 15% of length 50 ofouter cover 32 inboard of each of front waist edge 34 and rear waistedge 36. For example, the waist zone may extend longitudinally about 10%of length 50 of outer cover 32 inboard of each of front waist edge 34and rear waist edge 36. Outer cover 32 has a front waist zone extendinglaterally along the entire width of front waist edge 34, inclusive ofthe width of front side panels 46, if present. The front waist zoneextends longitudinally approximately 5 to 15% of length 50 of outercover 32 inboard of front waist edge 34. For example, the front waistzone may extend longitudinally about 10% of length 50 of outer cover 32inboard of front waist edge 34. Outer cover 32 has a rear waist zoneextending laterally along the entire width of rear waist edge 36,inclusive of the width of rear side panels 48, if present. The rearwaist zone extends longitudinally approximately 5 to 15% of length 50 ofouter cover 32 inboard of rear waist edge 36. For example, the rearwaist zone may extend longitudinally about 10% of length 50 of outercover 32 inboard of rear waist edge 36.

Outer cover 32 has two leg zones adjacent each longitudinally extendingside edge 26, extending laterally from each longitudinally extendingside edge approximately 10-25% of width 30 of outer cover 32 at thecrotch point, and extending longitudinally along width 30 of outer cover32. For example, the leg zones may extend longitudinally about 15% ofwidth 30 of outer cover 32. Outer cover 32 has an ear zone whichincludes all portions of outer cover 32 which extend laterally outboardfrom longitudinally extending side edges 26 (e.g., encompassing the sidepanels, if present).

Stretch Zones

Certain regions of outer cover 32 may require more extensibility and/orelastic recovery than other regions in order to accommodate variation inwearer geometry, movement of the wearer during use, or both of these.For example, the wearer's buttocks region can expand about 50% in thelateral direction as the wearer moves from a standing position to asitting or squatting position. Additionally, within a given weightrange, the various dimensions of a wearer, such as waist circumference,thigh circumference, rise through the crotch, etc., may varysignificantly. To provide for better fit, comfort, and ease ofapplication, the stretch properties of the outer cover may be differentin different regions to accommodate these variations. Increased lateralextensibility or elastic elongation in the rear region of the outercover as compared to the front region of the outer cover may serve tobetter conform to and cover the buttocks through movements or bodypositions of the wearer (including sitting and/or bending forward at thehips). For example the back waist region of the outer cover may includea zone which extends at least about 15%, or at least about 20%, under anapplied force of 5N in the Whole Product Back Extension test describedbelow. Greater extension may allow the outer cover to accommodate awider range of wearer shapes, sizes, and motions. In order to provide aconforming fit in all wearer body positions, the outer covermaterial—that is, the material or materials from which the outer coveris made—may extend 50% in the lateral direction under no more than 10 N,and more preferably 5 N, of applied force to accommodate buttocksexpansion during wearing.

Likewise, a zone of increased longitudinal elongation in rear region 20of outer cover 32 may serve to better conform to and cover the buttocksregion of the wearer as the wearer bends or squats. Also, a zone oflateral elongation at front waist 34 (i.e., increased extension ascompared to the crotch region) may allow the outer cover to accommodatewearer abdominal expansion when the wearer is in a seated position.Conversely, since relatively little lateral or longitudinal expansion ofthe body occurs in the front part of crotch region 18 of outer cover 32,this region may include a zone of lower, or even zero, elongation.

In addition to providing for differences in wearer geometry or motion,outer cover 32 may also provide sustained fit, resisting sagging andirrecoverable downward movement under stresses applied to the articlefrom bodily motion and/or increasing mass of bodily exudates in thearticle during the wearing period. A minimum magnitude of elasticrecovery force may be required in at least certain zones of outer cover32 to achieve this. For example, the elastic recovery force may behigher in the rear waist 36 of outer cover 32 than in the buttocksregion. While the outer cover material in the buttocks region may extendunder low forces to accommodate buttocks expansion during bodilymovement, the waist region may maintain a minimum level of elasticrecovery force to maintain a secure fit and anchoring of the articlearound the wearer's torso. Outer cover 32 may include a rear waist zonethat retains at least about 1.0N, 1.5N, or 2.0N “unload” force at 25%elongation in the Whole Product Back Extension test. A higher unloadforce may provide improved fit and resistance to sagging. Excessiveunload force may contribute to red marking or abrasion of the wearer'sskin. The magnitude of force which is excessive will vary with otherdetails of the construction of the outer cover (such as the coefficientof friction between the outer cover material and the skin) and thedelicacy of the skin contacted by the outer cover, which may varybetween locations on the same user (such as the hip and the perinealarea) as well as between different kinds of users (such as incontinentor menstruating adults and infants).

Different elastic properties can be provided in different zones by usingdifferent materials in the different zones. In some embodiments, outercover 32 may be fashioned from a single material that is treated orotherwise altered to manipulate its properties in different zones. Forexample, an elastically extensible material can be fixed into place atselected locations, as by sewing, gluing, hot-melting, etc., to “deaden”the elastic, thereby locally reducing or even eliminating the elasticproperties of the material. Alternately, a single, uniform material thatis inelastic until activated can be used, and activated only in thedesired zones. Elasticity and elastic recovery can be created orincreased by adding elastic fibers, strips, scrims, webs, films or bandsto the outer cover material. For example, one or more elastic bands canbe laminated into the zones with desired elastic properties. One or moreanchoring bands 52 may be used to increase elastic recovery. Anchoringbands are described, for example, in U.S. Provisional Patent Application61/144,883, filed Jan. 15, 2009. Of course, a combination of thesetechniques may be used to provide different levels of elasticity indifferent zones, and even different levels of elasticity in response todifferent forces (i.e., lateral forces, as from wearer respiration andmovement, or longitudinal forces from wearer movement and exudateloading).

Breathability and Skin Condition

Outer cover 32 may, in part due to the localized nature of bodilyexudate release associated with human anatomy, contain more urine and/orfeces in one region of the article than another. Regions of the articlehaving higher concentrations of bodily exudates often have an associatedhigher level of humidity between the article and the wearer's skin.Additionally, certain regions of the body covered by the article, e.g.,in the intertriginous and genital regions, have a higher concentrationof sweat glands, and often experience a higher amount of released sweat.These areas may have increased local humidity as a result. Increasedlocalized humidity near the skin can lead to over-hydration of the skin,which may contribute to erythema, diaper dermatitis, and/or increasedsusceptibility of the over-hydrated skin to abrasion. Accordingly, outercover 32 may have at least one zone having a higher breathability inthese regions associated with increased humidity. These zones may have aWater Vapor Transmission Rate (WVTR) as measured by the Mocon testdescribed below to allow sufficient water vapor from urine and/or sweatto leave the interior of the article, maintaining the skin hydration ata lower level. For example, outer cover 32 may have a zone having a WVTRof at least about 1200 g/m²/24 hr or 3000 g/m²/24 hr. Higher WVTRs maybe helpful when the ambient conditions are higher in temperature and/orhumidity, when the wearer is more active (e.g., perspires more), and/orwhen the diaper has a higher loading of urine or other liquid exudates(e.g., during overnight use or when the user is a “heavy wetter”). Thus,a WVTR of at least about 1200 g/m²/24 hr may indicate a serviceableouter cover in typical use, while a WVTR of at least about 3000 g/m²/24hr may indicate a serviceable outer cover under more challengingconditions.

In the past, outer covers for reusable absorbent articles have been madeof relatively thick films with very low water vapor transmission rates,often well below 1000 g/m²/24 hr (see Examples 5, 9, and 10, below). Onemethod of producing an outer cover for a reusable absorbent article witha more robust WVTR is to use a microporous film. However, microporousfilms exhibit minimal elastic extension and recovery. A breathable,stretchable outer cover may be desirable. For example, a stretchablewoven fabric may be used as the outer cover. A porous, stretchable wovenfabric allows air and water vapor to pass through. A higher WVTR mayalso be achieved by mechanically aperturing the outer cover, such thatair and water vapor can traverse the thickness of the outer cover.Liquid penetration can then be managed by controlling the aperture orpore size and/or by providing inner layer 58 of outer cover 10, whereinat least one of inner layer 58 and outer layer 60 is hydrophobic. Abreathable, stretchable outer cover with reduced liquid penetration mayalso be provided by employing more than one layer of a stretchable wovenfabric as the outer cover. In any of these embodiments, inner layer 58and outer layer 60 may have the same or similar properties, and providea higher WVTR by duplication of the barrier. In some embodiments, innerlayer 58 and outer layer 60 are different. For example, outer layer 60may be a soft, extensible layer with pleasant tactile and aestheticproperties, while inner layer 24 is a hydrophobic layer with desirablemoisture barrier properties. Inner layer 58 may have a greater elasticreturn force than outer layer 60, such that the pores of inner layer 58are generally maintained in a smaller, less open configuration, and,therefore, transmit less water.

The WVTR of outer cover 32 may be varied in different zones by usingdifferent materials in different zones. If outer cover 32 is made of asingle layer, the single layer may be pieced together of differentmaterials. If outer cover 32 is made of more than one layer, the layersmay be different materials which are not co-extensive, such that somezones have the breathability of the composite and some zones have thebreathability of only one of the layers. The WVTR may also be varied indifferent zones by using different treatments of the same material ormaterials in different zones. For example, different zones may havedifferent depths, frequency, or patterns of aperturing, possiblyincluding zones or portions of a zone which are not apertured. Possibletreatments include mechanical treatments, such as aperturing, as well asalternate treatments such as exposure to heat, compression or strain,and chemical treatments.

Fluid Penetration Resistance

Certain regions of outer cover 32, either in proximity to the anatomicexudate release points or the perimeter of an absorbent core, assembly,or insert 22, may be more likely to experience contact with urine,feces, or other exudates. Outer cover 32 may include zones of higherfluid penetration resistance in these regions as compared to otherregions of outer cover 32 to prevent leakage through outer cover 32 ontothe wearer's clothing or other environmental objects. Fluid penetrationresistance may be measured by the Mocon hydrohead test, and may varyfrom 5 mbar to 20-50 mbar or more over the surface of the outer cover.The greater the hydrohead value, the less likely it is that liquidexudates will be able to traverse the material making up the outer cover(as opposed to leaking along the edges of the outer cover, such as theleg openings 54 or waist opening 56).

Fluid penetration resistance may be decreased by aperturing the outercover, or by mechanically deforming or stretching the outer cover. Fluidpenetration resistance may be increased by adding additional layers ofthe same or different materials, or by treating one or more materials ina laminate. For example, the hydrophobic treatments described below mayalso increase the fluid penetration resistance of the outer covermaterial.

Hydrophobicity

As described above, certain regions of outer cover 32 may be more proneto contact with urine, feces, or other exudates. Outer cover 32 mayinclude zones having a greater hydrophobicity in these regions in orderto reduce the likelihood of fluid penetration and leakage.Alternatively, outer cover 32 may include zones of greaterhydrophilicity, or even absorbent capacity, in these regions in order tocontrol or trap the exudates and prevent them from flowing across outercover 32 to a perimeter, such as leg openings 54 or waist opening 56,where they may leak into the environment. The zones of differenthydrophilicity and/or hydrophobicity may be spaced in the lateral orlongitudinal directions in outer cover 32, or may be spaced through thethickness of outer cover 32 (e.g., via different layers). Thehydrophobicity (or hydrophilicity) of the outer cover may be measured bydetermining the contact angle of water with the outer cover material.

Hydrophobicity may be varied by using different materials havingdifferent inherent hydrophobicities. For example, part of outer cover 32may be fashioned from cotton and part of outer cover 32 may be fashionedfrom a polypropylene film with minimal pores or pinholes. Hydrophobicitymay also be varied by selectively coating part of outer cover 32.Hydrophobic treatments are well known, and include, for example, waxes,hydrophobic silicone compositions, proprietary treatments such asScotchgard™ Protector Repellent and Repel Teflon® Fabric Protector, andthe like. Hydrophobicity may also be varied by selectively layeringmaterials, in a bonded, partially bonded, or substantially unbondedlaminate. A hydrophobic material may be applied to selected areas ofouter cover 32 using any means known in the art, including, but notlimited to, spraying, coating, and laminating.

Static Coefficient of Friction

Certain regions of outer cover 32 contact regions of the wearer's body,such as the hip, buttock, and upper thigh regions, and may be morecapable than other regions of providing anchoring support to outer cover32. An outer cover having zones of higher static coefficient of frictionon the wearer-facing surface 62 in the regions may tend to haveincreased support and improved sustained fit during the wearing process.Additionally, certain regions of outer cover 32 may contact absorbentinsert 22 during wearing, while others may not. Outer cover 32 may havezones of higher static coefficient of friction in at least a portion ofthis insert contact area, such as crotch region 18 of outer cover 32, tominimize shifting of absorbent insert 22 within outer cover 32 duringwear that may lead to poor fit and leakage. Static coefficient offriction may be measured as described below, and may vary from 0.3 to0.4 or 0.5 or higher over the surface of the outer cover. In someembodiments, the static coefficient of friction may be greater than 0.8or 1.0.

The static coefficient of friction for a material depends in part on thematerial against which it is moving. Thus, the same zone may beconfigured to provide a relatively high static coefficient of frictionrelative to a first material on a first surface and a relatively lowstatic coefficient of friction relative to a second material on a secondsurface. For example, it may be desirable to configure crotch region 18of outer cover 32 such that wearer-facing surface 62 has a relativelyhigh static coefficient of friction relative to absorbent insert 22, andgarment-facing surface 64 has a relatively low static coefficient offriction relative to common fabrics (to reduce pilling or other damageto clothing during use) or to skin (to reduce the potential forirritation from incidental contact between the outer cover and theuser's skin, such as the user's inner thighs).

The static coefficient of friction may be varied by adding coatings orlayers having a high coefficient of friction, by mechanically deformingthe substrate to create a rougher surface, or by any other means knownin the art.

Test Methods

All testing is performed at 23°±2° C. and 50±2% relative humidity,unless otherwise specified.All samples are equilibrated at that environment for at least 2 hoursbefore testing.

Water Vapor Transmission Rate

Water Vapor Transmission rate (WVTR) is measured according to EDANA/INDAWorldwide Strategic Partners Method WSP 70.4 (08) using a Permatran-Wmodel 100K (MOCON, Minnesota, Minn.). The test method was run as per theWSP standard test, using a test apparatus temperature of 37.8° C., anitrogen flowrate of 120 SCCM, and the standard mode with 2 cycles and 5minute exam time. Each cell is individually adjusted to a relativehumidity (RH) of 60%±1.5%. The standard reference film (S/N 1008WK089from MOCON) should be run prior to testing the samples in order toensure that the equipment is running properly. The standard referencefilm results should be within±10% of the values reported by MOCON.

Using scissors or a die cut a specimen 35 mm in diameter. If the outercover is multilayered the specimen is run as the composite sample. Theside of the outer cover which normally faces the skin is oriented towardthe water for testing. Report the WVTR as g/m²/24 hr to the nearest 1g/m²/24 hr.

Hydrostatic Head Test

Hydrostatic head test is conducted as described in EDANA/INDA WorldwideStrategic Partners Method WSP 80.6 (50) using a TexTest FX 3000Hydrostatic Head Tester. The test was performed using the 100 cm² testhead, with a water temperature of 23±2° C. The test was modified toincrease the pressure at a rate 20 mbar/min. The test was terminated andpressure recorded after 3 separate drops are formed on the surface ofthe specimen. These drops must form in three different penetratingholes, and must originate 6 mm away from the edge of the clamp.

Using scissors, a specimen 14 cm by 14 cm is cut from the outer cover.If the outer cover consist of multiple layers, the layers are tested asa composite. The side of the outer cover which normally faces the skinis oriented toward the water for testing. If the size of the outer coverwill not permit sampling of a 14 cm by 14 cm specimen, use instead a 10cm by 10 cm sample and a 28 cm² test head. Report the Hydrostatic headpressure to±0.1 mbar.

Whole Product Back Extension Forces

Whole product back extension forces are measured on a constant rate ofextension tensile tester with computer interface (a suitable instrumentis the MTS Alliance using Testworks 4.0 Software, as available from MTSSystems Corp., Eden Prairie, Minn.) using a load cell for which theforces measured are within 10% to 90% of the limit of the cell. Both themovable (upper) and stationary (lower) pneumatic jaws are fitted with 1inch×1 inch diamond faced grips.

As used herein 100% strain means that the sample has been elongated by100% of its original length measured under no applied load. For example,a sample with an original length of 100 mm will have a 100% strain whenelongated to a length of 200 mm.

Program the tensile tester to extend the specimen to 100% strain at arate of 254 mm/min., hold at that strain for 30 sec. and then return to0% strain at 254 mm/min. After 60 sec. again extend the sample to 100%strain at 254 mm/min., hold for 30 sec. and then return to 0% strain at254 mm/min. Set the data acquisition rate to 100 Hz. From the forceversus % strain curve, program the software to report the extension (mm)at 5N of force on the first load cycle, the % strain (%) at 5N of forceon the first load cycle, and the force (N) at 25% strain on the firstunload cycle.

For a taped-type absorbent article: Set the gage length to the length195 as shown in FIG. 1. Zero the crosshead. Insert the specimen into theupper grips, aligning edge 154 of the panel that is proximal tolongitudinal centerline 12 with the lower edge of the grip face andclose the grips. Zero the load cell. Insert the other end of thespecimen into the lower grips aligning edge 154 of the panel that isproximal to longitudinal centerline 12 with the upper edge of the gripface, and close the grips. The specimen should be under enough tensionto eliminate any slack in the sample, but force measured by theinstrument must be less than 0.5N. Start the tensile tester's program,and record data.

For a pants-type absorbent article: Measure the waist circumference ofthe article. Divide the waist circumference by 2 to calculate a backwaist length. Fold the article such that the front or top portion of thewaist and the back or bottom portion of the waist are of equal length(i.e., the waist circumference divided by 2). Set the gage length to theback waist length. Zero the crosshead. Insert the specimen into theupper grips, aligning the edge of the waist of the folded article withthe lower edge of the grip face and close the grips. Zero the load cell.Insert the other end of the specimen into the lower grips aligning theedge of the waist of the folded article with the upper edge of the gripface, and close the grips. Make a T-shaped cut longitudinally throughthe front waist and laterally through the crotch of the article, suchthat the front and rear waist portions are separated. The specimenshould be under enough tension to eliminate any slack in the sample, butforce measured by the instrument must be less than 0.5N. Start thetensile tester's program, and record data.

For a front waist measurement: Measure the waist circumference of thearticle. Divide the waist circumference by 2 to calculate a front waistlength. Fold the article such that the front or bottom portion of thewaist and the back or top portion of the waist are of equal length(i.e., the waist circumference divided by 2, or the lesser of the frontand back waist lengths). Set the gage length to the front waist length.Zero the crosshead. Insert the specimen into the upper grips, aligningthe edge of the front waist of the folded article with the lower edge ofthe grip face and close the grips. Zero the load cell. Insert the otherend of the specimen into the lower grips aligning the edge of the frontwaist of the folded article with the upper edge of the grip face, andclose the grips. For a pants-type article, make a T-shaped cutlongitudinally through the back waist and laterally through the crotchof the article. The specimen should be under enough tension to eliminateany slack in the sample, but force measured by the instrument must beless than 0.5N. Start the tensile tester's program, and record data.

Report extension (mm) at 5N of force on the first load cycle to±1 mm,the % strain (%) at 5N of force on the first load cycle to±0.1%, and theforce (N) at 25% strain on the first unload cycle to±0.1 N.

Outer Cover Composite Extension Force

The Outer Cover Composite Extension Forces are measured on a constantrate of extension tensile tester with computer interface (a suitableinstrument is the MTS Alliance using Testworks 4.0 Software, asavailable from MTS Systems Corp., Eden Prairie, Minn.) using a load cellfor which the forces measured are within 10% to 90% of the limit of thecell. Both the movable (upper) and stationary (lower) pneumatic jaws arefitted with rubber faced grips wider than the width of the specimen. Thegage length is 25.4 mm and the data acquisition rate is 100 Hz.

Program the tensile tester to extend the specimen to 110% strain at acrosshead speed of 254 mm/min. and then return to the original crossheadposition. Program the software to report the force (N) at 50% strain and100% strain.

Using a JDC precision cutter (Thwing Albert) cut a 1″ wide strip in thelongitudinal direction of the outer cover that is 3″ long. If there aremultiple layers of the outer cover the specimen should be cut though alllayers. The composite should be tested as a whole and also as theindividual layers. Any single specimen (either composite or singlelayer) should only be tested once.

Set the gage length to 25.4 mm, zero the crosshead and zero the loadcell. Insert the specimen into the upper grips, aligning it verticallywithin the upper and lower jaws and close the upper grips. Insert thespecimen into the lower grips and close. The specimen should be underenough tension to eliminate any slack, but less than 0.05N of force onthe load cell. Start the tensile tester's program and collect data.

Report the force (N) at 50% extension for the composite (multi-layered)specimen to±0.01 N. Report the force (N) at 100% extension for each ofthe single layered specimens to±0.01 N.

Coefficient of Friction

The static coefficient of friction can be measured using ASTM Method D1894-01 with the following particulars. The test is performed on aconstant rate of extension tensile tester with computer interface (asuitable instrument is the MTS Alliance using Testworks 4 Software, asavailable from MTS Systems Corp., Eden Prarie, Minn.) fitted with acoefficient of friction fixture and sled as described in D 1894-01 (asuitable fixture is the Coefficient of Friction Fixture and Sledavailable from Instron Corp., Canton, Mass.). The apparatus isconfigured as depicted in FIG. 1.c of ASTM 1894-01 using a stainlesssteel plane with a grind surface of 320 granulation as the targetsurface. A load cell is selected such that the measured forces arewithin 10% to 90% of the range of the cell. The tensile tester isprogrammed for a crosshead speed of 127 mm/min, and a total travel of130 mm. Data are collected at a rate of 100 Hz.

The test specimen is cut into a square 6.35 cm by 6.35 cm with its sidesparallel and perpendicular to the longitudinal axis of the outer cover.The specimen is mounted onto the foam rubber side of the sled usingdouble sided adhesive tape (tape should be wide enough to cover 100% ofthe sled's surface). The specimen is oriented on the sled such that theskin facing surface of the outer cover will face toward the targetsurface and the longitudinal axis of the outer cover is parallel to thepull direction of the sled. The mass of the sled with mounted sample isrecorded to 0.1 gram. The surface of the stainless steel plane iscleaned with isopropanol between each analysis. To measure the staticcoefficient of friction against skin, the target surface is NaturinCoffi Film, Product# 101183, available from Globe Casing Company ofCarlstadt, N.J. To measure the static coefficient of friction againstthe absorbent insert, the target surface is an 18 gsm mattepolypropylene film from Clopay Plastics Products Company of Mason, Ohio.

The Static COF is calculated as follows:

Static COF=A _(S) /B

A_(S)=maximum peak force in grams force (gf) for the initial peak

B=mass of sled in grams

AATCC Test Method 124-2001, Modified

In a wash cycle, a component of an absorbent article, such as an outercover, is machine washed and machine dried according to the protocolfrom AATCC (American Association of Textile Chemists and Colorists) TestMethod 124-2001, with the selected parameters and variations listedbelow.

a) Per section 6, Apparatus and materials, a Kenmore 600 (HeavyDuty—Super Capacity Plus—Quiet Pak) is used for the automatic washingmachine, and a Maytag Commercial (such as model numbers MDE27MNACW,MDE15MNAYW, and MDE13MNACW) is used for the automatic tumble dryer.

b) Despite the instructions in Section 6, Apparatus and materials, thefollowing ballast is used: Test Fabric style 493 from Testfabrics, Inc,West Pittston, Pa., which is cotton sheeting, with a thread count of60×60, a weight of 151 gsm, and a size of 55′ by 39″.

c) Despite the instructions in Section 6, Apparatus and materials, theevaluation area is not configured according to section 6.7 and theapparatus of section 6.8 is not used. Instead, all visual evaluationsare performed under typical artificial lighting conditions (e.g.fluorescent light), which allows a person with normal vision to clearlysee.

d) Despite the instructions in Section 7, Test Specimen, the componentto be tested is (as necessary) entirely removed from the rest of theabsorbent article, and (to the extent allowed by the removal) thecomponent is tested as an undamaged whole. Up to three components of thesame type are washed simultaneously.

e) Regarding the machine wash in Section 8.2.2, use the “large” settingon the machine for the water level, select a wash temperature of 32+/−3°C. (90+/−5° F.), and a rinse temperature of 16+/−3° C. (60+/−5° F.).

f) Regarding the settings in Section 8.2.2, select Normal/Cotton Sturdy,which has a washing time of 12 minutes, an initial spin time of 6minutes, a refill time of 4 minutes, a rinse time of 5 minutes, and afinal spin cycle time of 6 minutes.

g) Regarding the Drying in Section 8.3, select Cotton Sturdy and Whites& Colors.

h) Despite the instructions in Section 8.5, the steps of conditioningand preconditioning are not performed.

i) Despite the instructions in Section 9, Evaluation, these evaluationsteps are not performed. Instead, the tested component is evaluated byone of skill in the art, to determine whether the testing has resultedin significant degradation to the appearance or performance of thearticle that would render it unsuitable for its intended functionalityand/or use.

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm.”

Every document cited herein, including any cross referenced or relatedpatent or application, is hereby incorporated herein by reference in itsentirety unless expressly excluded or otherwise limited. The citation ofany document is not an admission that it is prior art with respect toany invention disclosed or claimed herein or that it alone, or in anycombination with any other reference or references, teaches, suggests ordiscloses any such invention. Further, to the extent that any meaning ordefinition of a term in this document conflicts with any meaning ordefinition of the same term in a document incorporated by reference, themeaning or definition assigned to that term in this document shallgovern.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

1. A reusable outer cover for an absorbent article, the reusable outercover comprising: a front zone; and a rear zone; wherein the rear zonehas a greater percent extension than the front zone in the Whole ProductBack Extension test.
 2. The reusable outer cover of claim 1, wherein therear zone extends at least 50% under an applied force of 5N and has anunload force of at least 1.0N at 25% extension.
 3. The reusable outercover of claim 2, wherein the front zone extends at least 15% under anapplied force of 5N.
 4. A reusable outer cover for an absorbent article,the reusable outer cover comprising: a front zone; a crotch zone; and arear zone; wherein the crotch zone has a higher WVTR than the front andrear zones.
 5. The reusable outer cover of claim 4, wherein the crotchzone has a WVTR of at least 1200 g/m²/24 hrs.
 6. The reusable outercover of claim 5, wherein the crotch zone has a WVTR of at least 3000g/m²/24 hrs.
 7. The reusable outer cover of claim 4, wherein the crotchzone has a higher fluid penetration resistance than the front and rearzones.
 8. The reusable outer cover of claim 7, wherein the crotch zonehas a fluid penetration resistance of at least 5 mbar.
 9. The reusableouter cover of claim 7, wherein the crotch zone has a wearer-facingsurface comprising a first layer and a garment-facing surface comprisinga second layer, and the second layer is more hydrophobic than the firstlayer.
 10. The reusable outer cover of claim 9, wherein the second layeris more hydrophobic than the front and rear zones.
 11. A reusable outercover for an absorbent article, the reusable outer cover comprising: aside zone; a rear zone; a front zone; and a crotch zone; wherein theside, rear, and front zones have a higher static coefficient of frictionrelative to skin than the crotch zone.
 12. The reusable outer cover ofclaim 11, wherein the side, rear, and front zones have a staticcoefficient of friction relative to skin greater than 0.5.
 13. Thereusable outer cover of claim 11, wherein the crotch zone has a staticcoefficient of friction relative to skin less than 0.4.
 14. The reusableouter cover of claim 12, wherein the side zone has a higher staticcoefficient of friction relative to skin than the front and rear zones.15. The reusable outer cover of claim 14, wherein the side zone has astatic coefficient of friction relative to skin greater than 0.3. 16.The reusable outer cover of claim 11, further comprising an absorbentinsert removably situated against at least a portion of the crotch zone,wherein the crotch zone has a higher static coefficient of frictionrelative to the absorbent insert than the side, rear, and front zones.